ISO 9635-5:2014

Overview

ISO 9635-5:2014, "Agricultural irrigation equipment - Irrigation valves - Part 5: Control valves," specifies construction, performance requirements and test methods for hydraulically‑operated control valves used in irrigation systems. It applies to valves of DN 15 (1/2 inch) and larger, designed to operate in any position and to regulate flow, pressure or water level. The standard covers valves that are directly operated (spring/diaphragm), pilot‑operated, and valves that can also function as check valves. It is intended for use with water up to 60 °C, including water containing fertilizers and commonly used agricultural chemicals.

Key topics and technical requirements

• Design requirements: Valves must be designed in accordance with ISO 9635-1:2014 (general requirements). Manufacturers must declare working limits and any special installation/commissioning conditions.
• Mechanical strength: Tests for shell and pressure‑containing parts, obturator resistance to differential pressure, resistance to bending (bending moments defined by DN), and operating loads are specified.
• Watertightness and seat tightness: Internal/external pressure tests, seat leakage rates (Rate A required for level and pressure control valves), and maximum manual operating torque for override operation.
• Hydraulic characteristics: Flow coefficient (Kv) must be declared (measured per ISO 9644) and be within ±5% of the declared value. Regulation performance (flow, pressure, level) is verified using the normative test methods in Annexes A–C; measured regulation values should generally be within ±10% of manufacturer documentation unless tighter tolerances are provided.
• Chemical resistance: Materials and lubricants in contact with water must resist fertilizers and agricultural chemicals (refer ISO 9635-1:2014).
• Endurance: Annex D defines endurance testing; post‑endurance hydraulic and leakage performance must remain within specified limits.
• Conformity assessment: Type tests, production control and quality system requirements are included (see Clause 6).

Practical applications and users

• Manufacturers of irrigation control valves, valve designers and test laboratories use this standard to design, test and certify products for agricultural irrigation systems.
• System integrators, irrigation project engineers, procurement teams and regulatory bodies rely on ISO 9635-5:2014 to ensure valves meet safety, hydraulic and durability expectations for applications including drip, sprinkler and reservoir level control where exposure to fertilizers/chemicals is expected.

Related standards (for reference)

• ISO 9635-1:2014 - General requirements for irrigation valves
• ISO 9635-2:2014 - Isolating valves
• ISO 9644 - Test method for pressure losses in irrigation valves

Keywords: ISO 9635-5:2014, control valves, irrigation valves, agricultural irrigation equipment, Kv flow coefficient, hydraulic characteristics, watertightness, endurance testing.